1. Technical Field
The present invention relates to a piezoelectric motor that uses a piezoelectric element to drive a unit that is to be driven, a liquid ejecting apparatus using the piezoelectric motor, and a clock using the piezoelectric motor.
2. Related Art
A piezoelectric motor is a device that rotationally drives a rotating shaft using a piezoelectric actuator provided with a piezoelectric element. Here, the piezoelectric actuator used in the piezoelectric motor is provided with a vibrating member and a piezoelectric element held on one of the surfaces of the vibrating member. The piezoelectric element of which the piezoelectric actuator is configured has two electrodes sandwiching the piezoelectric layer.
Here, the piezoelectric layer is provided with a longitudinal vibration excitation region that elicits vertical vibrations in the piezoelectric element and a bending vibration excitation region that elicits bending vibrations in the piezoelectric element (for example, see JP-A-2007-267482).
The longitudinal vibration excitation region is provided toward the center of the piezoelectric layer in the widthwise direction, whereas two groups of bending vibration excitation regions are provided as pairs on either side of the longitudinal vibration excitation region, with one member of each pair being disposed on either side of the longitudinal vibration excitation region so as to be located diagonally opposite to the other member of the pair. Longitudinal vibration is performed by the piezoelectric actuator causing longitudinal vibration through the expansion/constriction of the longitudinal vibration excitation region in the longitudinal direction. Meanwhile, bending vibration is performed by the piezoelectric actuator repeating, in alternation, bending driving in which one pair of the bending vibration excitation regions is expanded while the other pair is constricted and bending driving in which the one pair of bending vibration excitation regions is constricted while the other pair is expanded. Repeating, in alternation, the longitudinal and bending vibrations results in driving that causes the ends of the piezoelectric element in the lengthwise direction to trace an elliptical orbit.
However, because the longitudinal vibration excitation region and bending vibration excitation region have in the past been formed by dividing a single electrode into five portions, there has been a problem in that there is a large number of wires to connect to the electrode, and thus a risk that the mass of the wiring may disturb the vibration of the piezoelectric element.
Furthermore, in the above-described configuration used in the past, multiple wires are connected to multiple electrodes, leading to an increase in the number of connection locations; thus there is a problem in that the vibration characteristics of the piezoelectric element will change due to heat, pressure, or the like arising during the connection process, making it difficult for the piezoelectric element to obtain uniform characteristics.